A major new exhibition at the National Museum of Scotland (NMS) is to be hit by strike action today.

The first of three planned days of industrial action by members of the Public and Commercial Services Union (PCS) will take place today from lunchtime at the Edinburgh institution, as well as on Saturday and Sunday.

Its new show, Ming: The Golden Empire, was due to open today and run until October. Last night the NMS said it did not know if the museum would open today.

The strikes are an ­escalation of a dispute over a weekend working allowance that has been ongoing since Boxing Day.

Lynn Henderson, Scottish Secretary of the PCS, said it was time for the Scottish Government and NMS to "invest in the people" who look after valuable works of art, "given that the museum is worth over £60m to the Scottish economy".

A spokesman for National Museums Scotland said: "It is regrettable that PCS has chosen to take this action, which is bound to have an impact on planned days out for tourists and locally based visitors, particularly at the beginning of the school summer holidays."

He added: "Weekend payments are no longer common in the culture and tourism sector across the UK. No member of staff has received a pay cut following the introduction of new contracts."