A number of part-time firefighters in the north-east of Scotland are expected to join their full-time colleagues in strike action.

Grampian Fire Brigade said some part-time staff had joined the Fire Brigades Union (FBU) to allow them to support their colleagues.

The FBU has demanded a 40% pay rise and has planned 36 days of walk-outs before Christmas.

Firefighters who are members of the Retained Firefighters' Union are planning to continue working.

Fire facts

Scotland has 4,588 full-time firefighters 2,799 part-time firefighters 1,200 volunteer firefighters 520 fire engines 30 aerial appliances 14 rescue and emergency vehicles 59 other specialist vehicles 109 Green Godesses will be used in Scotland

However, part-time work is also carried out by a number of FBU members and firefighters with no union affiliation.

The four stations at Elgin, Peterhead, Dyce and Kintore are expected to be affected by part-time workers' action.

It is believed that some retained crews do not want to operate engines while full-time staff are picketing the stations.

Walter Stewart, Scottish secretary of the RFU, condemned the strike action.

Mr Stewart said he had not received any communication from part-time firefighters who were planning to strike.

His theory was that some part-time firefighters working at stations with full-time crews may have decided to support their colleagues.

'Full-time presence'

He told BBC Radio Scotland: "One can understand that, because it creates for the future a hostile environment as it did in the 1977 strike.

"These people have to work alongside their full-time colleagues.

"But you have a lot of retained units who are stand-alone, these units have no full-time presence and are members of the RFU."

Mr Stewart said the firefighters in the non-mixed units had already expressed their intention to continue working.

RFU members will continue to work

He also claimed that some firefighters were stitching from the FBU to the RFU because they did not want to go on strike.

"Our membership is increasing by more than we are losing," he said.

However, FBU executive council member John McDonald said there had been an "incredible" influx of retained firefighters joining the FBU over the summer.

He also claimed that the RFU was unwilling to fight for more pay but willing to accept any gains achieved by the larger union.

Meanwhile, politicians have clashed after Scottish National Party leader John Swinney called on the government to step aside and allow negotiations to continue on the pay dispute.

He also called for the introduction of a new pay formula and a "commensurate" level of pay for firefighters.

'Come clean'

However, Public Service Minister Andy Kerr accused Mr Swinney of seeking publicity for himself.

"John Swinney must now come clean," said the Labour MSP.

"If he supports the pay claim he must tell us how he would pay for it and the subsequent pay claims.

"If he supports the review, he must call on the firefighters to postpone their action until the review is completed."

A spokesman for the SNP leader replied: "We believe negotiations of this nature should be between the employers' body and the unions, and that government interference is unhelpful."