The number of properties being put up for rent in the nation's wealthiest suburbs has soared, as unemployment fears intensify and struggling mansion owners try to avoid selling during the recession.

Agents in prestige suburbs say an oversupply of properties for lease has caused rents to fall by at least 25% and forced landlords to wait longer before securing a tenant.

The prestige rental market is also suffering because of the sharp downturn in the corporate sector, with fewer executives relocating and less generous rental allowances for those who do.

But the glut of top-end rentals is proving a bonanza for cashed-up tenants who can now live at a desirable address, often in a bigger and better property, and negotiate with agents over the rent.

The Australian