Updated 11.13am with more details.

A company part-owned by mega developer Joseph Portelli has entered into a €4.8 million agreement to buy an illegally-built garage complex overlooking a protected valley in Mosta.

The promise-of-sale agreement is subject to the Planning Authority issuing permits to develop the land, which is located in an ODZ area, where development is forbidden.

CF Estates Finance said in a public announcement last month that its acquisition of the 1,600 square metre complex is subject to permits being issued. A previous attempt in 2007 by the owners to develop the area into 24 residential units and four penthouses was abandoned.

Former Labour foreign minister Evarist Bartolo flagged the plans in a Facebook post on Tuesday, saying the garage complex was illegally built in 1989.

The promise-of-sale agreement is valid until July 2024, according to the announcement by CF Estates Finance plc.

The company has already paid a 10% deposit – €480,000 – as part of the deal.

Corporate records show that Portelli is the main shareholder of CF Estate’s parent company, CF Estates. The other shareholders include Portelli’s business partners Clifton Cassar and Duncan Micallef. Both companies were set up last year.

"The seller himself said that it was Portelli who bought it (the site) since he is the only one with the power to get what he wants from the Planning Authority," Bartolo claimed in his Facebook post.

Bartolo said the promise of sale agreement was signed weeks ago and that the sum paid led him to wonder how big the project for the valley would be.

When neighbours tried to raise concerns on social media, they were told they were only complaining because they would lose their views, he said.

"As if it was a sin to speak up against continued overdevelopment," Bartolo said.