(Updates with FinMin quote, analyst, paras 2,5,7)
ANKARA, July 23 (Reuters) - Turkey's top court on Wednesday struck down a key tax-raising measure proposed by the government to meet IMF-backed budget targets, but let a second tax stand.
Seeking to allay market fears of further tensions with the fund, Finance Minister Kemal Unakitan said Turkey would meet any revenue shortfalls in the budget with fresh measures.
The court's decision may complicate a latest IMF review of Turkey's $16 billion pact already delayed since early June by slow progress on reform. Turkey hopes the fund's board can meet by the start of August to approve a latest $500 million loan.
The Constitutional Court let stand a supplementary property tax the government estimates will raise 650 trillion lira, but ruled unconstitutional a supplementary motor vehicle tax, set to raise 1,100 trillion lira ($783 million).
"This was expected but is still disappointing as it adds extra pressure on the government to find fiscal measures to ensure the 6.5 percent of GNP primary surplus target is met," Bear Stearns said in a research note.
The government has sought new sources of revenues as it struggles to keep to tough IMF-inspired budget targets designed to ensure it safely pays down a massive domestic debt load swollen to some $125 billion by financial crisis in 2001.
"If the extra measures I have taken are cancelled then my revenues will fall... The government will take the extra measures and meet the shortfall," Unakitan told reporters.
The ruling Justice and Development Party (AKP) had already pledged the IMF at the weekend to find some $1.8 billion in extra revenues over and above the planned vehicle tax and other steps it has taken.
Officials have already collected 393.7 trillion lira from the motor vehicle tax. ($1=1404700 Turkish Lira)