Seek has downgraded its full-year profit guidance after first-half profit fell five per cent due to investments it says will provide long-term benefits.

Revenue for the six months jumped 21 per cent to $766.6 million thanks to earnings from its Chinese jobs portal division Zhaopin, but rising costs pushed the online jobs advertiser's profit down to $99.3 million from $104.4 million a year earlier.

Seek incurred extra costs from the privatisation of Zhaopin, and now expects early stage venture investment for the full year of about $40 million to $45 million, compared to a previous estimate of $35 million to $40 million.

Chief executive Andrew Bassat said the company ramped up investment to accelerate growth following a strong performance in its early-stage ventures portfolio.

Seek now expects a full-year profit of slightly less than last year's of $53.2 million, ended June 30.

At 1233 AEDT, Seek shares were 6.8 per cent higher at $18.52, with investors apparently impressed by Zhaopin's growth and Seek's long-term growth potential.

The company will pay an interim dividend of 24 cents, fully franked, unchanged from the previous year.

Also Wednesday, Seek announced it would appoint chief executive of construction management software company Aconex Leigh Jasper as non-executive director, effective from April.

SEEK H1 PROFIT DIPS

* Net profit down 5pct to $99.3m

* Revenue up 21pct to $757.2m

* Fully franked interim dividend unchanged at 24 cents