AN MSP has launched a stinging attack on his fellow SNP backbenchers by accusing them of failing to effectively scrutinise the Government when sitting on Holyrood committees.

John Mason, who represents Glasgow Shettleston, said some of his colleagues in the SNP were "overly protective of the party line" and that that the attitudes of parliamentarians, rather than the structure of the committee system, needed to change.

Holyrood's committees have a crucial role in holding the Government to account by scrutinising legislation as it makes its way through parliament, obtaining evidence from expert witnesses, launching enquiries and making amendments to proposed laws. However, the SNP's historic victory in 2011 has meant the party holds a majority on most of the 19 committees, with votes often split along party lines.

Mr Mason, in a submission to the Holyrood's standards committee which is considering possible reforms, said: "I do not really think that changing the system in itself is the answer. Rather my feeling is that the answer is in the attitude of the members of the Scottish Parliament and in particular the attitude of backbench members within the majority party which is currently the SNP."

Mr Mason, a former Glasgow MP who defeated Margaret Curran in a Westminster by-election in 2008, said that there were some success stories, singling out the finance committee's scrutiny of Freedom of Information reforms which led to ministers abandoning a move to keep correspondence from senior Royals secret and increasing the number of organisations subject to the law.

However, the deputy convenor of Holyrood's finance committee added: "I do think there needs to be a realisation amongst backbench members in the same party as the Government that part of their role is to scrutinise legislation and policy and hold the Government to account. It seems to me that some backbenchers are good at this but some seem to be overly protective of the party line.

"The Government backbenchers need to be prepared to challenge the Government and also the opposition members need to be constructive at times and not just oppose for the sake of opposing."

The presiding officer, Tricia Marwick, has attempted to reform Holyrood's committee system which has come under fire during the current parliament. Opposition MSPs have accused the Nationalists of using their voting power to block potentially embarrassing inquiries and water down reports critical of government policy, while there has been a suggestion some SNP backbenchers have asked ministers softball questions drawn up by party advisors in advance.

But proposals to move towards elected committee convenors, rather than having the roles allocated by party bosses, was rejected by the SNP-dominated standards committee earlier this year. The system has proved successful at Westminster, allowing MPs such as Margaret Hodge a high-profile platform to interrogate ministers and powerful private sector bosses.

A cross-party group of MSPs are to discuss possible reforms on Thursday, with Liberal Democrat Alison McInnes backing up much of Mr Mason's position with her own submission ahead of the meeting.

She said that Holyrood's committee system was in need of reform with the extensive new powers set to be transferred to Holyrood over the course of the next parliament making their role even more vital.

She added: "My colleagues and I would also be interested in whether any reforms could seek to curb the culture of the party whip and enhance the independence of committee members. Scottish Liberal Democrats firmly believe that committees are at their best when all their members work in the public interest. Every member has a responsibility to scrutinise legislation and policies proposed by their own party just as closely as they would if they were proposed by an opponent."