A consortium involving Macquarie Bank's Korean private equity arm and MBK Partners is poised to acquire a 30 per cent stake in South Korea's second-biggest cable TV operator and intends to buy the remaining shares, say people familiar with the deal.

Macquarie Korea Fund has signed a preliminary deal to purchase the stake from Goldman Sachs for about $650m and agreed to a follow-on deal to jointly hold the stake with MBK.