Police have started investigations into irregular quotations received by the Ministry of National Development and the Urban Redevelopment Authority.

In its report released yesterday, the Auditor-General's Office (AGO) highlighted irregularities in a "significant number" of quotations by contractors for public projects.

It said checks at MND revealed "tell-tale signs" indicating irregularities in 49 out of 71 work orders involving star rate items.

The AGO said it had concerns about the authenticity of quotations for the star rate items, for which rates are not listed in the contract. The total value of these items came up to $250,000.

The work orders were from the same contractor for building facilities works, and the checks arose from a complaint about irregularities.

A similar pattern was seen in one of URA's infrastructure projects. Checks revealed irregularities in nine out of 16 quotations by a contractor for star rate items for four contracts with changes to the scope of works.

The estimated value of these four contract variations came up to $55,000. While payment has not been made, the AGO was concerned that these quotations may be used to assess if the payment claims were reasonable.

The AGO recommended that the government bodies refer their cases to the police, which they did.

MND has informed the AGO that it will have tighter controls, like more stringent checks on quotations and suppliers.

It said it will step up training for staff in the areas of contract management and detecting irregularities. URA said it will ensure a "thorough, independent re-evaluation" of the value of the variation works in question before paying.

This is not the first time the AGO has recommended referring cases to the police. In 2014, it flagged possible procurement wrongdoings at the National Library Board. A former officer was later charged with corruption.