Foreigners buying houses in Victoria will be slugged with a $330-million tax, under a radical state budget plan to force international investors to pay "their fair share".

Under Labor's highly controversial move, foreign nationals - many from China - will pay a new tax equivalent to 3 per cent of the purchase price of houses, raising $279 million over four years.

That means a Chinese national buying an $800,000 property will pay an extra $24,000, in addition to about $43,000 in stamp duty charges.

Foreign housing investors will also pay an extra 0.5 per cent in land tax from 2016 on new and existing properties, raising $53.5 million over four years.