In its Energy & Resources 2012 report, commercial law firm Squire Sanders said 2011 deals rose 7% in value but volume of deals dropped 9%.
Energy deals dominated, worth $396.5 billion, ahead of mining with $127.8 billion worth of M&A, though mining deals dropped by 8% to 267.
The largest mining deal was the $10.4 billion merger of KazakhGold and Russia's Polyus Gold in June, the sixth largest deal overall, followed by Alpha Natural Resources' $8.1 billion takeover of Massey Energy Company and Barrick Gold's $7.4 billion acquisition of Equinox Resources.
More than 50% of the total value of deals went to North American targets, but only 44% of the funds came from North American bidders.
Australia remains as the largest M&A market for mining, registering 59 deals worth $22 billion last year.
The report highlighted the continued emergence of Asian investors, which increased their share of the deals contribution to 25%.
Cross-border M&A reached the highest level on record at 42% of the deals and 47% of the total deal value.
"This is the highest level on record, suggesting that regional boundaries in the global industry are starting to dissolve, and will continue to do so as foreign buyers look for more stake acquisitions to reduce financial and operational risk," Squire Sanders Global Practice Group leader for corporate and corporate finance William Downs said.
Looking ahead, M&A is likely to remain focused on the Asia-Pacific region and North America, with cross-border activity growth likely to continue.
"Alongside the economies of Southeast Asia, an emerging market to watch, perhaps, is Sub-Saharan Africa which is the only region where mining is more active than energy in terms of potential targets," Downs said.
M&A is already off to a strong start this year, driven by the proposed $88 billion merger between Swiss companies Glencore International and Xstrata.
"Deal activity slipped somewhat in 2011 though the shake up from the Glencore-Xstrata planned mega-merger is likely to transform the landscape in 2012," Squire Sanders Perth-based Global Industry Group leader for Energy & Natural Resources Duncan Maclean said.
"Cash-rich players will be looking to bolt-on acquisitions and opportunities to maintain market share - and certainly the appetite for raw materials in emerging markets in Asia - not just China but growing economies such as Vietnam - will surely act as a buy-side driver."