The workers, who are members of the Unite union, are employed by Interserve Industrial Services.

According to the union, the crux of the dispute is that when construction work started at the £154 million Glasgow Recycling & Renewable Energy Centre (GRRC) site, Polmadie Road, Polmadie, Glasgow about 18 months ago the scaffolders and labourers were employed on CIJC nationally agreed pay rates that are now less than workers subsequently employed on rates equivalent to the NAECI national agreement or greater.

Unite regional officer Stephen Deans said: “This dispute has been running since last June. What appears to have happened is that Interserve employed the workers going on strike on the CIJC rate.

“But the firm and their subcontractors are paying new workers on the site at the higher nationally NAECI agreed rate or greater. They have had to employ people from across Scotland and even from outside Scotland, so they have had to pay more to attract the travelling workforce.

“What we are calling for is pay parity for all workers on the site that has a workforce of between 300 to 400 workers. This could mean an uplift of between £4 and £5 an hour for our members, depending on their jobs.

“We had a meeting with the Interserve management (on Thursday) and they refused to consider pay parity. This is very disappointing.

“We want management to get back around the table and seriously negotiate on the issue of pay parity – we hope the two 48-hour strikes will focus management’s mind.”

The workers’ 48-hour strike began at 00.01 on Monday. This will be followed by a 48-hour strike, starting at 00.01, on Tuesday 3 May.